The present invention relates generally to payload fairings for launch vehicles and, more particularly, to an interface between the fairing and the launch vehicle.
A launch vehicle is used to launch a payload into the orbit around the earth. The payload, however, needs protection from the atmosphere created at launch. High temperatures and pressures created may damage a sensitive payload. A fairing is typically used to protect the payload. The fairing surrounds the payload in the nose portion of the launch vehicle. Typically, the fairing is detachably mounted to the upper stage of the launch vehicle. As soon as the rocket leaves the atmosphere, the fairing is explosively separated from the launch vehicle and discarded.
Spacecraft are subjected to a broad range of potentially damaging environmental conditions during flight, including shock. The two highest sources of shock to the payload occur during payload fairing separation and payload separation. Traditionally, a mechanical shock attenuation device such as shock rings are employed between the fairing and the payload attachment hardware. This, however, leaves a direct path in place for shock transmission. Although the shock rings employed soften the shock to the payload, they are operationally fragile, cumbersome to install, and add unnecessary weight to the launch vehicle. Further, modern spacecraft have more highly sensitive components than previous spacecraft, and therefore must be designed to sustain high flight shock and vibration environments, at the expense of useful payload-to-orbit mass. Spacecraft must be subject to expensive time-consuming ground tests to validate payload capabilities against severe flight environment including random vibration, acoustics and shock. The spacecraft separation via a clampband is typically the dominant shock source to which components are qualified. Over the past several years, spacecraft manufacturers have funded the development of several low shock clampband systems to fly on various launch vehicles. Spacecraft are typically qualified to this environment by performing two clampband release tests. If a low shock clampband is used, the fairing now becomes the dominant shock source. Spacecraft must still be qualified to higher g""s via the clampband release test because it would be to difficult and expensive to qualify the spacecraft using a full scale fairing separation test to envelope the shock.
It would therefore be desirable to provide a structure that reduces the amount of shock on the payload during fairing separation.
The present invention provides a magnetic interface between the payload fairing and the launch vehicle whereby the fairing is levitated a distance above the launch vehicle when the fairing is separated from the launch vehicle.
In one aspect of the invention, a launch vehicle assembly has a launch vehicle body having a first slot therein. A first magnet is disposed within the first slot. A fairing assembly is positioned adjacent to the vehicle body. The fairing assembly has a second slot therein positioned opposite the first slot. A second magnet is disposed within the second slot so that the second magnet repels the first magnet.
In another aspect of the invention, a method of operating a launch vehicle comprises:
positioning a payload fairing adjacent to a launch vehicle body;
contacting the payload fairing with the launch vehicle body above a predetermined force on the payload fairing;
levitating the payload fairing relative to the launch vehicle body below a predetermined force on the payload fairing; and
after levitating the payload fairing, releasing the payload fairing from the lunch vehicle.
One advantage of the invention is that by mitigating shock on the payload during fairing release, less damage to payload is possible. Also, launch and launch vehicle performance does not need to be sacrificed due to added weight of previously known adapting methods.
Other advantages and features of the present invention will become apparent when viewed in light of the detailed description of the preferred embodiment when taken in conjunction with the attached drawings and appended claims.